There is perhaps no more abused or abusive HTML document device than
the <blink> tag extension for text content currently
supported by, thank heaven, only the Netscape browser.[1]

[1]
Few web surfers use Internet Explorer, so you rarely and thankfully
won't find many HTML documents using the browser's equally tacky
<marquee> feature.

It works by alternating the color of the text enclosed between the
<blink> tag and its end tag
(</blink>)--incessantly! It's not only ugly
(reminiscent of the very bad video-text displays on a hotel TV), but
it's excruciatingly annoying. The reader can't turn it off except to
scroll beyond that portion of the document or hyperlink out of the
document altogether. [the section called "Physical Style Tags"]

Okay, so it grabs readers' attention to make an important point. Just
make sure it's a very important point. And here's a tip: Make it easy
for the reader to get by the blinking segment in your document.
Surround it with empty space or with pleasant, but vacuous content
that they don't have to read.